The issue of fugitive emissions around industrial facilities, chemical storage and transportation is an increasingly important problem to solve. Governmental limits on allowable levels of polluting or noxious substances in fugitive emissions are becoming more stringent and more strictly enforced. In the oil and gas industry in particular, vapours that become released from oil and gas refinement, processing and storage must be essentially free of Benzene, Toluene, Ethyl-benzene, and Xylene (BTEX), sulfur compounds and volatile organic carbon molecules (VOCs) before being ventable or otherwise releasable to the environment. These chemicals in fugitive emissions are a constant problem from oil field carriers and tanks.
As the air within a tank, pipe, vessel or carrier is displaced with fluids from oil field wells, that air will inevitably contain at least a minimal level of typical complex oil field vapours, including VOCs. These are generally classified by carbon length, methane being C1, octane being C8 for example. In addition to VOCs there are a subset of VOC's referred to as BTEX, which are a complex composite of organic molecules which have low odour threshold and in some cases are known carcinogenic molecules. In some cases there are also sulfur bearing organic molecules which can be thiols, mercaptans and H2S which have a very low threshold limit value (TLV). While the presence of these chemicals may only be in the parts per million (ppm) range, it is still required that these chemicals be removed substantially entirely.
A number of systems have been developed in the past and tested on the market with varying results.
Liquids have commonly been used as a filter medium to remove chemicals from gas streams that are bubbled through liquid. However, handling of liquid filtration media is complicated, heavy and can lead to spills. Filtration using liquid media often leads to solids and sludge which are difficult to remove. Filtration equipment using liquid filtration media is also typically not very flexible in how it can be arranged or connected, without risking spilling. Furthermore, spent liquid media is often a hazardous substance which needs special care and increase costs to handle and dispose of.
EP 110262061 describes an air filter system where a sorbent filter is made in a pleat web pack design. US 20130292001 describes an air purification system, specifically for a gas mask filter cartridge and a method to fill a sorbent inlet. U.S. Pat. No. 4,559,066 describes a filter cartridge where a sorbent bed receives the gas stream and gas flow radially outward from the sorbent bed, it is a low capacity system with a pleat pack filter on an outer surface of the system, and with a permanent cartridge. U.S. Pat. No. 2,728,409 describes a method of filtering gases with a vaned, radially directed gas inlet contained in a canister.
However, there is still a need for a design that effectively removes noxious substances from fugitive emissions streams that is portable, reusable, simple to install, flexible in its installation arrangement, can vary in capacity of filtration needs and can be safely hauled to and from an industrial site.